Document Type : Main File (First File)


1 1-Department of Earth Sciences, Faculty of Sciences,University of Tabriz, 51664, Tabriz, Islamic Republic of Iran. 2-Research Institute for Fundamental Sciences (RIFS), 51664, Tabriz, Islamic Republic of Iran

2 1Department of Earth Sciences, Faculty of Sciences,University of Tabriz, 51664, Tabriz, Islamic Republic of Iran

3 3Department of Geology, Faculty of Sciences ,University of Urmia, Urmia, Islamic Republic of Iran

4 4Institut für Erd und Umweltwissenschaften, Universität Potsdam, 14476 Potsdam, Germany


Metapelitic rocks in the Gasht area include micaschist, kyanite schist, andalusite schist, garnet schist, staurolite schist, cordierite schist and sillimanite schist. Tourmaline occurs as accessory mineral in all of these rock types. These schists are metamorphosed regionally and are affected by contact metamorpism subsequently. Based on the textural relations and the fact that CaO and TiO2 contents in the studied tourmalines are low, they are formed during regional metamorphism. They appear in the rock matrix and as inclusions in other minerals, especially biotite  and albite. The studied tourmalines are of alkali type and are rich in dravite end-member. Cl and F contents are below the detection limit testifying for hydro-tourmaline nature of the studied minerals. Na and K are higher in the X-site in comparison with Ca. Low Ca shows neglegible amounts of Ca end-member or uvite. Mg content is much higher than Fe in the structure of the studied tourmalines, which are not zoned or show weak zoning  and are grown  at  nearly constant P-T conditions. These tourmalines are crystallized from pelitic to psammitic protoliths in equlibrium with a fluid phase, rich in Al. Boron in fluid more likely was from the boron adsorbed on clay minerals surface in the protolith, released during metamorphism and boron from B-bearing mica breakdown during high tempertaure metamorphism, while boron released from the subducting oceanic crust is not a likely source for tourmaline crystallization in the studied rocks since there is no evidence for tourmaline in the associated oceanic crust mafic rocks.  


Main Subjects

Altherr R., Topuz G., Marschall H., Zack T. and Ludwig T. Evolution of a tourmaline-bearing           lawsonite eclogite from Elekdag area (Central Pontides, N Turkey): evidence for infiltration of slab derived B-rich fluids during exhumation. Contrib. Mineral. Petrol., 148: 409–425 (2004).
2. Bačík P., Meres S. and Uher P. Vanadium-bearing tourmaline in metacherts from Chvojnica, Slovak             Republic: Crystal chemistry and multistage evolution. Canad. Mineral., 49: 195-206 (2011).
3. Berryman E., Wunder B., Rhede D., Schettler G., Franz G. and Heinrich W. P–T–X controls on Ca and        Na distribution between Mg–Al tourmaline and fluid. Contrib. Mineral. Petrol., 171. DOI:              10.1007/s00410-016-1246-8 (2016).
4. Berryman E., Wunder B., Ertl A., Koch-Muller M., Rhede D., Scheidl K., Giester G. and Heinrich W. Influence of the X-site composition on tourmaline's crystal structure: investigation of synthetic K-dravite, dravite, oxy-uvite, and magnesio-foitite using SREF and Raman spectroscopy. Physic. Chem. Mineral., DOI: 10.1007/s00269-015-0776-3 (2015).
5. Bosi F. and Lucchesi S. Crystal chemical relationships in the tourmaline group: Structural constraints on chemical variability. Am. Mineral.,92:1054–1063 (2015).
6. Crawford M.A. A summary of isotopic age data for Iran, akistan and India. In: Libre a lá́ memoire               l'a A.F. de lapparent. Memoire hors-serie 8.Soc. Geolog. de France, 251-260 (1977).
7. Davis R.G., Hamzepour G., Jones, C.R. and Clark, G.C. Geology of the Masuleh sheet (Northwest              Iran). Geol. Surv. Iran,. Report 24:110 (1972).
8. Dutrow B., Foster C.T. Jr. and Henry D. J. Tourmaline-rich pseudomorphs in sillimanite zone       metapelites:  Demarcation of an infiltration front. Am. Mineral., 84:794–805 (1999).
9. Dutrow B. and Foster C.T. Jr. Constraints on metamorphic fluid from irreversible thermodynamic modeling of tourmaline pseudomorph formation. Geol. Soc. Am. Abst. Prog., 24:A218 (1992).
10. Dutrow B. L. and Henry D. J. Tourmaline: A Geologic DVD. Elements, 7: 301-306 (2011).
11. Harraz H.Z. and El-Sharkaway M.F. Origin of tourmaline in the metamorphosed Sikait pelitic belt, South eastern desert, Egypt, J. Afric. Earth Sci., 33:391-416 (2001).
12. Hawthorne F.C. and Henry D.J. Classification of the minerals of the tourmaline group. Eur. J.     Mineral., 11: 201-215 (1999).
13. Hazarika P., Mishra B. and Pruseth K. L. Diverse Tourmaline Compositions from Orogenic Gold Deposits in the Hutti-Maski Greenstone Belt, India: Implications for Sources of Ore-22. Forming Fluids. Econom. Geol., 110: 337-353 (2015).
14. Henry D. J. and Dutrow B. L. Evolution of tourmaline in metapelitic rocks: diagenesis to melting, Geol. Soc. Am. Abstr. Progr., 22:A125 (1990).
15. Henry D. J. and Dutrow B. L. Metamorphic tourmaline and its petrologic applications. Rev. Mineral. Geochem., 33, p. (1996).
16. Henry D.J., Dutrow B.L. and Selvestone J. Compositional asymmetry in replacement tourmaline: an example from the Tauern Window, Eastern Alps. Geol. Material. Res., 4:1-18 (2002).
17. Henry D. J. and Guidotti C.V. Tourmaline as petrogenetic indicator mineral: an example from the staurolite-grade metapelites of NW-Maine. Am. Mineral., 70:1-15 (1985).
18. Holtz F. and Johannes W. Effect of tourmaline on melt fraction and composition of first melts in quartzofeld­spathic gneiss. Eur. J. Mineral., 3:527-536 (1991).
19. Kawakami T. Tourmaline and boron as indicators of the presence, segregation and extraction of melt in pelitic migmatites: examples from the Ryoke metamorphic belt, SW Japan. Transact. Royal Soc. Edinburgh: Earth Sci., 95:111-123 (2004).
20. Kretz R. Symbols for rock forming minerals. Am. Mineral., 68:277-279 (1983).
21. Krosse S. Hochdrucksynthese, Stabilität und Eigen­schaften der Borsilikate Dravit und Kornerupin, sowie Darstellungund Stabilitäts verhalt eneines neuen Mg-Al borates. Thesis, Ruhr-Universität Bochum, Germany (1995).
22. Kutzschbach M., Wunder B., Rhede D., Koch-Müller M., Ertl A., Giester G., Heinrich H. and Franz           G. Special Collection: Advances in Ultrahigh-Pressure Metamorphism: Tetrahedral boron in natural and synthetic HP/UHP tourmaline: Evidence from Raman spectroscopy, EMPA, and    single-crystal XRD. Am. Mineral. 101:93-104 (2016).
23. Leeman W. P. and Sisson V. B. Geochemistry of boron and its implications for crustal and mantle processes. Boron: Mineralogy, Petrology and Geochemistry (Grew, E. S. and Anovitz, L. M., eds.), Min. Soc. Am. Rev. Mineral., 33:645-708 (1996).
24. London D. Magmatic-hydrothermal transition in the Tanco rare-element pegmatite: Evidence from fluid inclusion and phase equilibrum experiments. Am. Mineral., 71:376-395 (1986).
25. London D., Morgan G.B. and Wolf M. B. Boron in granitic rocks and their contact aureoles. In Mineral. Soc. Am. Rev. Mineral., 33:299-330 (1996).
26. London D. and Manning D. A. C. Chemical variation and significance of tourmaline from southwest England. Econom. Geol.,90:495-519 (1995).
27. Manning D. A. C. Chemical and morphological Variation in tourmalines from the Hub Kapong batholith of Peninsular Thiland. Min. Mag.,45:139-147 (1982).
28. Michaeli R. Study of metamorphic rocks from the Gasht and Asalam areas, north Iran.Unpublished Ph.D. thesis. University of Tabriz (2013).
29. Omrani H., Moazzen M., Oberhänsli R., Tsujimori T., Bousquet R. and Moayyed M. Metamorphic history of glaucophane-paragonite-zoisite eclogites from the Shanderman area, northern Iran. J. Metamorph. Geol., 31:791-812 (2013a).
30. Omrani H., Michaeli R. and Moazzen M. Geochemistry and petrogenesis of the Gasht peraluminous granite, western Alborz mountains, Iran. Neues Jahrb. Geolog. Palaontol. Abhandl., 268:175-189 (2013b).
31. Ota T., Kobayashi K., Katsura T. and Nakamura E. Tourmaline breakdown in a pelitic system: implications for boron cycling through subduction zones. Contrib. Mineral. Petrol., 155:19-32 (2008).
32. Palmer M.R. and Swihart G.H. Boron isotope geo­chemistry: an overview. In Boron: Mineralogy, Petrology and Geochemistry (E.S. Grew & L.M. Anovitz, eds). Rev. Mineral. 33:709-744 (1996).
33. Robbins C.R. and Yoder H. S. Jr. Stability relations of dravite, a tourmaline. Carnegie Inst. Wash. Yearbook, 61:106-108 (1962).
34. Spicer E.M., Stevens G. and Buick I.S.The low-pres­sure partial-melting behaviour of natural boron-            bearing metapelites from the Mt. Stafford area, central Australia. Contrib. Mineral. Petrol., 148:160-170 (2004).
35. Trumbull R.B. and Chaussidon M. Chemical and boron isotopic composition of magmatic and hydrothermal tourmalines from the Sinceni granite-pegmatite system in Swaziland. Chem. Geol., 153:125-137 (1999).
36. Tsang T. and Ghose S. Nuclear magnetic resonance of 1H, 7Li, 11B, 23Na and 27Al in tourmaline (elbaite). Am. Mineral., 58:224-229 (1973).
37. Ugiyama K. S., Rima H. A., Onno H. K. and Awamata T. K. Distribution of Mn in pink elbaitic  tourmaline from Mogok, Myanmar. J. Mineral. Petrol. Sci. 111: 1-8 (2016).
38. Van Hinsberg V. J., Henry D. J. and Marschall H. R. Tourmaline: An ideal indicator of its host environment. Canad. Mineral., 49:1-16 (2011).
39. von Goerne G., Franz G. and Wirth R. Hydrother­mal synthesis of large dravite crystals by thechamber method. Europ. J. Mineral., 11:1061-1078 (1999).
40. Werding G. and Schreyer W. Experimental studies on borosilicates and selected borates. In:Grew E.S. and Anovitz L. M. (EDS) Boron: mineralogy, petrology and geochemistry. Mineral. Soc. Am. 2nd Ed., 133:117-163 (2002).
41. Wunder B., Berryman E., Plessen B., Rhede D., Koch-Muller M. and Heinrich W. Synthetic and natural ammonium-bearing tourmaline. Am. Mineral., 100(1): 250-256 (2015).